A California-based super PAC has fired the first outside salvo in the 12th District congressional race with a mailer criticizing state Sen. Malcolm Graham, a Charlotte Democrat.

Progressive Kick, a liberal group that has endorsed state Rep. Alma Adams of Greensboro, is spending $50,000 against Graham, one of six Democrats running for the seat vacated by U.S. Rep. Mel Watt, who stepped down in January to lead the Federal Housing Finance Agency.

The mailer features a milk carton with Graham’s picture under the word “Missing.” It calls him “a No-Show in Senate Job.”

The N.C. Center for Public Policy Research found that Graham missed all or part of 10 of 106 legislative days in 2013. That tied him for 42nd in attendance in the 50-member Senate.

“I make no apologies about being a husband and father who has to provide for his family,” Graham said Tuesday. “It’s a shame that Mrs. Adams and others feel the need to go negative.”

Curtis Ellis, a spokesman for the liberal super PAC, said the mailer is going to people expected to vote in the 12th District primary.

“We spend our money efficiently,” he said. “We communicate with people who turn out in primaries.”

That Adams’ ally is targeting Graham suggests it believes he’s her strongest opponent in Tuesday’s primary. If no one gets 40 percent, the top two move to a July 15 runoff.

“Obviously she believes she has to win this thing in May because she can’t win in July,” said Graham. “I’m just keeping focused on what I can control and what I can’t.”